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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #314960

Title: Identification and genome characterization of genotype B and genotype C bovine parainfluenza type 3 viruses isolated in the United States

Author
item Neill, John
item Ridpath, Julia
item VALAYUDHAN, BINU - Texas A&M University

Submitted to: BioMed Central (BMC) Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2015
Publication Date: 5/15/2015
Publication URL: http://handle.nal.usda.gov/10113/61230
Citation: Neill, J.D., Ridpath, J.F., Valayudhan, B.T. 2015. Identification and genome characterization of genotype B and genotype C bovine parainfluenza type 3 viruses isolated in the United States. BioMed Central (BMC) Veterinary Research. 11:112. DOI: 10.1186/s12917-015-0431-8.

Interpretive Summary: Bovine respiratory disease (BRD) is a major concern to cattle producers in this country. There are a number of pathogens, both viral and bacterial, that contribute to BRD. One, bovine parainfluenza 3 virus (BPI3V), has been known for years and is included as a constituent of bovine vaccines sold in the U.S. The virus strains found here are categorized as genotype A viruses. Two other genotypes are known to exist, termed genotypes B and C. These have been described in Australia and Asia, respectively. All genotypes are 80-82% identical at the nucleotide level. In a recent survey of BPI3V isolates from Texas, it was found that genotype B and C BPI3V are circulating in domestic livestock herds. This was an unexpected finding. Until now, there has been no evidence of the existence of these genotypes in the U.S. In addition, a preliminary neutralization study indicated that there are perhaps significant antigenic differences amongst the genotypes. Coupled with the amount of sequence divergence of the different genotypes, current diagnostic tests and vaccines may not be adequate to detect the genotype B and C. viruses. This is the topic of ongoing investigations.

Technical Abstract: Background: Bovine parainfluenza 3 viruses (BPI3V) are respiratory pathogens of cattle that cause disease singly but are often associated with bovine respiratory disease complex (BRDC) in conjunction with other viral and bacterial agents. Bovine vaccines currently contain BPI3V to provide protection against the virus, but there is no current information regarding the BPI3V strains that are circulating in the U.S. Methods: A project was initiated to sequence archival BPI3V isolates to study viral evolution over time. This was done with a deep sequencing protocol that generated sequences of multiple RNA virus genomes simultaneously. Using this procedure, the genomic nucleotide sequence of 6 BPI3V isolates was determined and compared to each other and to sequences available in GenBank. Serum cross-neutralization titers were also determined using APHIS reference serum and virus. Results: Analysis of the BPI3V sequences revealed that, in addition to the genotype A viruses previously described in the United States, there were two additional genotypes of BPI3V circulating that had been described only in Australia (genotype B) and Asia (genotype C). The U.S. genotype B and C isolates showed some divergence from the Australian and Asian strains; the genotype B viruses were 93% similar to the Australian Q5592 strain and the genotype C viruses were 98% similar to the 12Q061 strain that was described in South Korea. Overall, the three genotypes were 82 to 84% identical to each other and 80% identical to the most similar human PI3V. Cross-neutralization studies using an APHIS/NVSL BPI3V reference serum showed that neutralization titers against the genotype B and C viruses were 4- to >16-fold less then the titer against the APHIS genotype A reference BPI3V strain, SF-4. Conclusions: This study clearly demonstrated that genotypes B and C of BPI3V, previously thought to be foreign to the U.S. are indeed circulating in domestic livestock herds. Based on virus neutralization using polyclonal antisera, there were antigenic differences between viruses from these genotypes and the genotype A viruses that are included in currently marketed bovine vaccines. Further study of these viruses is warranted to determine pathogenic potential and cross-protection afforded by vaccination. Keywords: deep sequencing; virus genome; paramyxovirus; virus genotype